I would definitely be very cautious about thiaminase. Also, I'd like to point out that it's very easy to offer an animal what looks like a wonderful, complete diet, yet still have them develop subclinical nutritional deficiencies. They may pick out favorite foods that don't have enough of one vitamin or mineral, and over time they will develop problems. And because they creep up slowly, these problems can be hard to notice, and hard to diagnose. And you cannot treat if you don't know what's wrong. Unless a keeper has devoted a LOT of time, effort, and scientifically-based research into invertebrate nutrition, I would strongly advise playing it safe and dusting at least some of the food items that are being offered. Look at it as a form of insurance toward the health and well-being of your pet. For myself, not only am I new to herps, I am not very good at raising invertebrates. I think I'm actually averaging 50% deaths in nearly a dozen different species. I've got to be realistic, I just can't seem to take good care of anything that doesn't have a backbone. There is simply no way I'm going to trust that I've raised them appropriately and can forego supplemental dusting. (Plus, at the rate I'm going, I am seriously not saving ANY money by attempting to set up feeder colonies. Someone else could probably do it on a shoestring budget and have them thrive. But that person is not me!)